The present invention relates to a turning insert comprising a pair of longitudinally extending surfaces enclosing an acute angle and forming a wedge-shaped insert body, a forward end of said insert arranged at the wider portion of the insert body which carries a cutting edge, a rearward end arranged at the narrower portion of the insert body and a shoulder. The cutting edge has a circular shape and a diameter which exceeds the thickness of the insert. The insert has a chip breaking device radially inside the cutting edge which device has a mainly circular shape.
The U.S. Pat. No. 3,705,447 shows a turning insert which comprises a partly circular cutting edge which connects to straight cutting edges for outwards facing. The connection between the circular portion and the straight portions weakens the insert. Furthermore, the rake face of the insert does not have any chip forming means and therefore the insert achieves a negative geometry. Thus, this type of geometry transfers large forces from the work piece to the holder carrying the insert.
One object of the present invention is to shape an insert such that it can perform a plurality of turning operations.
Another object is to adapt the insert for good chip control, irrespective of feed direction.
Still another object is to provide an insert that cuts with a varying setting angle.